The suspects were believed to be targeting vulnerable and elderly residents by pretending to be legitimate tradespeople.

A 24-year-old from Cranbrook, a 46-year-old from Orpington and two men from Erith aged 20 and 31 years were arrested on suspicion of fraud, by overpricing for building work and repairs.

Police are warning about rogue traders. Stock image

They have all been released pending further enquiries.

It was part of a national day of action on Wednesday, involving officers from Kent Police, Kent County Council and Medway Trading Standards, HM Revenue and Customs, the Environment Agency and Home Office Immigration Enforcement.

Searches were conducted at premises connected to suspected rogue trading and illegal waste disposal, including farms and businesses where checks were made on workers.

Supt Tim Cook said: "Rogue traders prey on the most vulnerable in society and we are determined to bring to justice these criminal gangs who are often responsible for stealing large amounts of money from those who can least afford it.

"This operation allowed us to work with other agencies to arrest offenders and gain some significant evidence relating to their criminal activities.

"Rogue traders need to be left in no doubt that we will find them and leave no stone unturned to seize any cash suspected to be proceeds of their crimes."